Crank runout on primary side... any ideas?

[1340evo]

I've seen a few figures quoted up to 0.012"??

I'm seeing about .006"... is this normal / Okay at this distance?

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[jsachs1]

When flywheels come in for a rebuild, mostly for rod bearings, I always check run out before disassembly.
Average is .005" on the motor sprocket side, and .001" - .003" on the pinion side. Sportsters are usually a little farther out.
I true them after rebuild to .000"- .0015"
John

[1340evo]

Thanks John.. so may be a tad above average (that said, it's being pushed by pistons etc so in a free state it could measure better)... so about what you'd expect?... Maybe something to do when the days get longer... I get a bit of vibration at around 3000 rpm.... but it will push through it.. think this could be the reason.. or won't you even see this?

Did see another post where an Evo had been measured exactly the same at .006".... may be they are all like that

[Burnout]

Also when you make a measurement like that you need to insure the bearing preload is maintained.

Doing it the way you have pictured is sort of a crap shoot, without something holding the bearing together you don't know if it is in the correct position.

Also checking right next to the bearing is not going to show much deflection you want to measure at the end of the shaft.

The proper way to check that is to pull the crank and put in between centers and check the runout at the bearing surface.

Might be better to just spin the crank in the cases and watch the end of the crank for wobble, if you see ANY it is likely out of spec.

[1340evo]

Hi.. that is the end of the shaft.. the other bit you see in front is the nut that goes through the compensator sprocket.. Its a tight thread but no idea if you could trust a measurement from that?

Also spinning it around is a problem as everything is still connected. Not sure how you make it tight without putting it back together or making a spacer sleeve to nip it up??

[1340evo]

Hi.. that is the end of the shaft.. the other bit you see in front is the nut that goes through the compensator sprocket.. Its a tight thread but no idea if you could trust a measurement from that?

Also spinning it around is a problem as everything is still connected. Not sure how you make it tight without putting it back together or making a spacer sleeve to nip it up??

[Burnout]

It's not an effective test without properly clamping the bearing.

Like I said, If you can see any wobble at all, it needs to come apart.